General:
* Ambiguous
* Indefinite
* Unclear
* Fuzzy
* Uncertain
* Imprecise
* Indistinct
* Opaque
* Nebulous
* Cloudy
* Abstract
* General
More specific:
* Elusive (difficult to grasp or understand)
* Ephemeral (lasting for a very short time)
* Transient (lasting only for a short time)
* Fleeting (lasting for a very short time)
* Shadowy (not clear or well-defined)
* Misty (unclear or confused)
* Hazy (unclear or confused)
* Unformed (not yet developed or defined)
The best word to use will depend on the specific context. For example, "ambiguous" might be a better choice if the meaning is open to interpretation, while "nebulous" might be better if the meaning is unclear or undefined.